The primary objective of this study is to determine whether Multiple Sclerosis patients differ from normal controls in their neuroendocrine response to seroto-nergic stimulation & to examine whether these differences are related to depression, suicidal ideation & behavior, length of illness & functional impairment. By comparing the serotonin-induced neuroendocrine response of depressed and non-depressed MS patients with healthy controls, the proposed study will examine whether serotonergic defects are inherent in MS or a byproduct of depression....